Public Knowledge About S&T
As the scientific and technical content of modern life grows, citizens increasingly need to be more scientifically literate to make sound public policy and personal choices. In developing an internationally agreed upon approach to conceptualizing and measuring scientific literacy, the Organisation for Economic Co-operation and Development (OECD) (2003) noted that literacy had several components:
Current thinking about the desired outcomes of science education for all citizens emphasizes the development of a general understanding of important concepts and explanatory frameworks of science, of the methods by which science derives evidence to support claims for its knowledge, and of the strengths and limitations of science in the real world. It values the ability to apply this understanding to real situations involving science in which claims need to be assessed and decisions made…
Scientific literacy is the capacity to use scientific knowledge, to identify questions and to draw evidence-based conclusions in order to understand and help make decisions about the natural world and the changes made to it through human activity. (pp. 132–33)
As the reference to changes made through human activity makes clear, the OECD definition encompasses an understanding of technology. In addition, OECD takes the view that literacy is a matter of degree and that people cannot be classified as either literate or not.
A good understanding of basic scientific terms, concepts, and facts; an ability to reason well about issues involving S&T; and a capacity to distinguish science from pseudoscience are indicators of scientific literacy. (For a different perspective on scientific literacy, see sidebar "Asset-Based Models of Knowledge").
Americans need to comprehend common scientific and technological terms such as DNA or molecule and recall commonly cited facts so they can make sense of what they read and hear about S&T-related matters. Whether they turn their attention to congressional debates over stem cell research or to instructional videos or pamphlets explaining how to use a newly purchased electronic device, the messages they get presuppose some basic knowledge of terms, concepts, and facts. For S&T, as for other topics, even people with superior reasoning and cognitive skills are at a disadvantage when they lack basic information, especially if others take such information for granted and make statements that build on it (Hirsch 2006).
Appreciating the scientific process can be even more important than knowing scientific facts. People often encounter claims that something is scientifically known. If they understand how science generates and assesses evidence bearing on these claims, they possess analytical methods and critical thinking skills that are relevant to a wide variety of facts and concepts and can be used in a wide variety of contexts.
An additional indicator of how well people apply scientific principles in real world contexts is how they assess pseudoscientific claims, which adopt the trappings of science to present knowledge claims that are not grounded in the systematic methodology and testing associated with science.
U.S. survey data indicate that many Americans cannot provide correct answers to basic questions about scientific facts and do not reason well about selected scientific issues. Residents of other countries, including highly developed ones, perform no better, on balance, when asked similar questions. In international comparisons of scientific knowledge and reasoning, then, American adults appear to rank somewhat better than American middle and high school students (see chapter 1, "Elementary and Secondary Education"). Any generalizations about Americans’ knowledge of science must, however, be tentative, given the measurement-related uncertainties discussed elsewhere in this chapter.
Understanding Scientific Terms and Concepts
U.S. Patterns and Trends
U.S. data do not show much change over time in the public’s level of factual knowledge about science.[11] 
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Factual knowledge of science is positively related to level of formal schooling, income level, and number of science and math courses taken. In addition, the oldest respondents are less likely than others to answer the questions correctly ).
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The factual knowledge questions that have been repeatedly asked in U.S. surveys involve information that was being taught in grades K–12 when most respondents were young. Because science continually generates new knowledge that reshapes how people understand the world, scientific literacy requires lifelong learning so that citizens become familiar with terms, concepts, and facts that emerged after they completed their schooling. In 2006, the General Social Survey (GSS) asked Americans questions that tested their knowledge of two topics that historically have not been central to the standardized content of American science education: nanotechnology and the Earth’s polar regions. For all but the youngest respondents, several of the questions concerned knowledge that was too new for them to have learned it in school. Nonetheless, survey respondents who scored relatively well on the questions that have been asked repeatedly over the years also exhibited greater knowledge of these two topics ).).
If Americans’ performance in answering factual knowledge questions concerning science can be deemed disappointing, the same is true for their performance in other areas of knowledge (see sidebar, "Science Knowledge and Civic Knowledge"). Survey data of varying quality have been interpreted to indicate that Americans, especially the young, do not know enough about history, civics, geography, and politics, and are not sufficiently interested in these and other domains of knowledge that, like scientific knowledge, can serve as a foundation for understanding the world around them (Bauerlein 2006; Gravois 2006).
International Comparisons
Adults in different countries and regions have been asked identical or substantially similar questions to test their factual knowledge of science.[14] Knowledge scores for individual items vary from country to country, and no country consistently outperforms the others ).
Science knowledge scores vary considerably across the EU-25 countries ));
Evolution and the "Big Bang"
In international comparisons, U.S. scores on two science knowledge questions are significantly lower than those in almost all other countries where the questions have been asked. Americans were less likely to answer true to the following scientific knowledge questions: "human beings, as we know them today, developed from earlier species of animals" and "the universe began with a huge explosion." In the United States, 43% of GSS respondents answered true to the first question in 2006, about the same percentage as in every year (except one) that the question has been asked. In other countries and in Europe, the comparable figures were substantially larger: 78% in Japan, 70% in China and Europe, and more than 60% in South Korea. Only in Russia did less than half of respondents (44%) answer true. Among the individual countries covered in the 2005 Eurobarometer survey, only Turkey’s percentage answering true to this question was lower than the U.S. percentage (Miller, Scott, and Okamoto 2006). Similarly, Americans were less likely than other survey respondents (except the Chinese) to answer true to the big bang question. In the most recent surveys, less than 40% of Americans answered this question correctly compared with over 60% of Japanese and South Korean survey respondents.
Americans’ responses to questions about evolution and the big bang appear to reflect factors beyond unfamiliarity with basic elements of science. The 2004 Michigan Survey of Consumer Attitudes administered two different versions of these questions to different groups of respondents. Some were asked questions that tested knowledge about the natural world ("human beings, as we know them today, developed from earlier species of animals" and "the universe began with a big explosion"). Others were asked questions that tested knowledge about what a scientific theory asserts or a group of scientists believes ("according to the theory of evolution, human beings, as we know them today, developed from earlier species of animals" and "according to astronomers, the universe began with a big explosion"). Respondents were much more likely to answer correctly if the question was framed as being about scientific theories or ideas rather than as about the natural world. When the question about evolution was prefaced by "according to the theory of evolution," 74% answered true; only 42% answered true when it was not. Similarly, 62% agreed with the prefaced question about the big bang, but only 33% agreed when the prefatory phrase was omitted. These differences probably indicate that many Americans hold religious beliefs that cause them to be skeptical of established scientific ideas, even when they have some basic familiarity with those ideas.
Surveys conducted by the Gallup Organization provide similar evidence. An ongoing Gallup survey, conducted most recently in 2004, found that only about a third of Americans agreed that Darwin’s theory of evolution has been well supported by evidence (Newport 2004). The same percentage agreed with the alternative statement that Darwin’s theory was not supported by the evidence, and an additional 29% said they didn’t know enough to say. Data from 2001 were similar. Those agreeing with the first statement were more likely to be men (42%), have more years of education (65% of those with postgraduate education and 52% of those with a bachelor’s degree), and live in the West (47%) or East (42%).
In response to another group of questions on evolution asked by Gallup in 2004, about half (49%) of those surveyed agreed with either of two statements compatible with evolution: that human beings developed over millions of years either with or without God’s guidance in the process. However, 46% agreed with a third statement, that "God created human beings pretty much in their present form at one time within the last 10,000 years or so." These views on the origin of human beings have remained virtually unchanged (in seven surveys) since the questions were first asked in 1982 (Newport 2006).
For almost a century, whether and how evolution should be taught in U.S. public school classrooms has been a frequent source of controversy (see sidebar, "Evolution and the Schools"). The role of alternative perspectives on human origins, including creationism and intelligent design, and their relevance to the teaching of science, has likewise been contentious. When Gallup asked survey respondents in 2005 whether they thought each of three "explanations about the origin and development of life on earth (evolution, creationism, and intelligent design) should or should not be taught in public school science classes" or whether they were "unsure," for each explanation more Americans chose "should" than chose either of the other alternatives ).
In other developed countries, controversies about evolution in the schools have also occurred, but more rarely. However, signs of opposition to the theory of evolution are emerging in Europe (Nature 2006).
Understanding the Scientific Process
U.S. surveys have used questions on three general topics to assess trends in Americans’ understanding of the process of scientific inquiry. One set of questions tests how well respondents apply principles of probabilistic reasoning to a series of questions about a couple whose children have a one-in-four chance of suffering from an inherited disease.[16] A second set of questions deals with the logic of experimental design, asking respondents about the best way to design a test of a new drug for high blood pressure. An open-ended question probes what respondents think it means to "study something scientifically." Because probability, experimental design, and scientific method are all central to so much research that claims to be scientific, these questions are highly relevant to how respondents evaluate scientific evidence.
There appears to be a modest tendency for Americans to score better on these inquiry questions in recent years, especially when the questions are analyzed together in an inquiry index ).).
Pseudoscience
The large numbers of Americans who regard astrology as at least somewhat scientific is an indicator that many Americans do not reliably distinguish between scientific and nonscientific knowledge claims. Available national data cannot differentiate those who misapply what they think are scientific criteria from those who in some respects reject conventional scientific criteria, even though they are familiar with them.
About one-third of Americans in 2006 said they believed that astrology was at least "sort of scientific." This proportion was almost exactly the same as in 2004. However, the 2004 and 2006 surveys indicate an apparent decline in the perception of astrology as scientific: the percentage of Americans who viewed astrology as not at all scientific was higher in these 2 years than it ever was in the 10 other times that this question was asked between 1979 and 2001 ).
Notes
[11] Survey items that test factual knowledge sometimes use readily comprehensible language even at the cost of some scientific imprecision. This may prompt some highly knowledgeable respondents to feel that the items blur or neglect important distinctions, and in a few cases may lead respondents to answer questions incorrectly. In addition, the items do not reflect the ways that even established scientific knowledge evolves as scientists accumulate new evidence. Although the text of the factual knowledge questions may suggest a fixed body of knowledge, it is more accurate to see scientists as making continual, often subtle, modifications in how they understand existing data in light of new evidence.
[12] Early NSF surveys used additional factual knowledge indicators, which were combined to form an aggregate indicator. Bann and Schwerin (2004) performed statistical analyses on this and other groups of indicators to produce shorter scales that involved fewer questions and required less time to administer, but were functionally equivalent to the scales that used additional items (e.g., had similar measurement properties and yielded performance patterns that correlated with similar demographic characteristics). For factual knowledge, Bann and Schwerin produced two alternative scales that, except for one item, used identical questions. One of these scales was administered in 2004, and the other was substituted in 2006. Appendix table 7-4 presents trend data using each scale. To enable aggregated comparisons of 2004 and 2006 results, it includes the average numbers of correct answers to the group of overlapping items from those 2 years.
[13] The two nanotechnology questions were asked only of respondents who said they had some familiarity with nanotechnology, and a sizable majority of the respondents who ventured a substantive answer (i.e., not "don't know") answered the questions correctly. To measure nanotechnology knowledge more reliably, researchers would prefer a scale with more than two questions.
[14] Even small, apparently nonsubstantive differences in question wording can affect survey responses. U.S. surveys, for example, have asked respondents whether or not it is true that "it is the father's gene that decides whether the baby is a boy or a girl." In contrast, the 2005 Eurobarometer asked whether or not it is true that "it is the mother's genes that decide whether the baby is a boy or a girl." To a scientifically knowledgeable respondent, these questions are equivalent. To other respondents, however, they may not be. Research has shown that some survey respondents have an "acquiescence bias"—when given the opportunity to do so, they tend to provide positive responses to questions and are therefore more likely to answer true than false (Schaeffer and Presser 2003). Thus, the U.S. question is probably easier to answer correctly than the Eurobarometer question; in other words, in two equally knowledgeable populations, more people would get the U.S. question right. Although Americans score better on this topic than Europeans, it is possible that this has as much or more to do with acquiescence bias as it does with scientific knowledge.
[15] In its own international comparison of scientific literacy, Japan ranked itself 10th among the 14 countries it evaluated (National Institute of Science and Technology Policy 2002).
[16] Early NSF surveys used additional questions to measure understanding of probability. Through a process similar to that described in endnote 12, Bann and Schwerin (2004) identified a smaller number of questions that could be administered to develop a comparable indicator. These questions were administered in 2004 and 2006, and appendix tables 7-9 and 7-10 record combined probability responses using these questions; appendix table 7-9 also shows responses to individual probability questions in each year.
